Over the last decade or so, many companies have installed networks with one or more local area networks in order to allow their employees access to various network resources. To improve efficiency, enhancements have been added to local area networks such as wireless access. Based on this enhancement, wireless local area networks (WLANs) have been and continue to be utilized by more and more companies.
Typically, a WLAN supports communications between a number of wireless devices (e.g., wireless stations “STAs”) without any required line of sight for such communications. In current network configurations, multiple Access Points (APs) are coupled to a wired network, such as an Ethernet network for example, and each AP operates as a relay station by supporting communications between resources of the wired network and the STAs. Data communications can be performed in accordance with a unicast, broadcast or multicast transmission scheme.
A multicast transmission scheme involves the distribution of packets to selected groups of wireless devices within the WLAN. These multicast groups can change dynamically, where the wireless devices may decide to join or leave a multicast group at any time, and may be a member of more than one multicast group.
Normally, to join a multicast group, a STA initiates a request to be included in a multicast session as a member of the multicast group. The request is performed in accordance with Internet Group Management Protocol (IGMP). IGMP is a communication protocol used to manage the membership of Internet Protocol (IP) multicast groups. More specifically, in accordance with the IGMP protocol, the STA informs a multicast router that it wants to receive transmissions directed to a particular multicast group (IGMP JOIN message) or that it no longer wants to receive messages directed to that multicast group (IGMP LEAVE message).
Currently, multicast communications are not efficiently supported by WLANs, especially centralized WLANs where multicast data streams are routed through a wireless network switch. Since multicast data streams are routed through the wireless network switch, this switch is currently responsible for replicating multicast data streams, and where applicable, encrypting such data streams with multicast keys. Replication at the wireless network switch is performed by software, which may cause unacceptably high transmission delays when supporting an increasing number of wireless stations.
As a result, there is a desire to alter the operations of a WLAN, especially centralized WLANs, so that most or all of the multicast data processing is handled by device(s) other than the centralized wireless network switch.